Battery Drains Overnight

[Cbobalulu]

I have a 1994 LS400 that the battery will drain to 4.5v overnight. I put in a new battery and it was dead the next day. I drove the car all this past week but I would disconnect the positive cable every time I parked the car for more than 30 minutes. I would connect it first thing in the morning and disconnect it when I got to work then connect it back up when I went home after work and then disconnected it after I got home and left it off overnight then started the same procedure the next day. I drove it all week without a problem. When the car is running the voltage at the battery is 14.4v which tells me that the alternator is ok. I hooked up an ammeter to the positive terminal and then to each of the positive leads (individually) and there was only .001 or 1 milliamp of current on the lead going to the alternator and nothing on the lead going to the starter. I thought there would be a large current draw since my battery would lose 8v in 12 hours. I have disconnected the trunk bulb, power to the CD changer, and power antenna but still the battery will drain overnight if positive leads are left connected to the battery. Any ideas what would drain the battery overnight that would not obviously be seen or heard.

CLowe

[IS400]

I have a 1994 LS400 that the battery will drain to 4.5v overnight. I put in a new battery and it was dead the next day. I drove the car all this past week but I would disconnect the positive cable every time I parked the car for more than 30 minutes. I would connect it first thing in the morning and disconnect it when I got to work then connect it back up when I went home after work and then disconnected it after I got home and left it off overnight then started the same procedure the next day. I drove it all week without a problem. When the car is running the voltage at the battery is 14.4v which tells me that the alternator is ok. I hooked up an ammeter to the positive terminal and then to each of the positive leads (individually) and there was only .001 or 1 milliamp of current on the lead going to the alternator and nothing on the lead going to the starter. I thought there would be a large current draw since my battery would lose 8v in 12 hours. I have disconnected the trunk bulb, power to the CD changer, and power antenna but still the battery will drain overnight if positive leads are left connected to the battery. Any ideas what would drain the battery overnight that would not obviously be seen or heard.

CLowe

You need to put the meter on the positive lead and ground it to the engine and see what kind of amp draw you have when the car is off. I'd say you are doing harm to your new battery cycling it like this.

You can also start jumping across fuses with your meter to check what is actually drawing power also. My guess is a pretty big short somewhere. Most components fail electrically 'open' but you probably have a closed circuit somewhere as you have already guessed.

If you can isolate the general area of the problem you are going to save loads. I had a boyfriend with a C5 corvette and he paid thousands for GM to NOT find the electrical problem and ended up ditching the car until his neighbor told him about some obscure factory defect with the starter circuit, which was a dealer paid fix and solved the problem. The dealer would not give him his money back for the hours and hours of diagnostic bills though...

Good luck!